Most often the answer I get is that Rival Wings doesn't have a lot to earn from, and thus why its been a dead PVP mode, and preferring to play Frontlines instead because there is a lot more to be earned in it.
So why not just have the achievements & Mounts from Frontlines be linked up with Rival Wings?
Put everything under the same umbrella.
Like Frontlines Horse Mount: Can be earned from victories in Frontlines or Rival Wings.
and while we're at it, have Rival Wings be part of the Roulette.
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Strangely, I'm kind of surprised people are not playing Rival Wings more often considering Rival Wings matches are much more quicker than Frontlines if you just need some tomestomes.
I know this seems like a messy idea, but unless they can update Rival Wings to have more things to earn in it I'm not sure what else can be done.
Another thing I've read this is purely a North American problem, seems like Rival Wings is fine and dandy on the Japanese servers (I have no idea what is going on with Euro Servers).